Project Summary/Abstract NIOSH conducts activities to assure safe and healthful conditions for American workers. This proposed project addresses a NIOSH mission objective for innovative solutions that provide practical methods to identify and measure hazards at a reasonable cost in high-risk occupations (e.g. mining). The mining industry presents particularly challenging safety and health needs. Despite well-regulated safety procedures, accidental explosions and toxic gas inhalation continue to cause coal miner deaths. To help prevent such tragedies, technologies are needed that sense and measure, from a distance, concentrations of explosive or other life-threatening hazards including methane (CH4), carbon monoxide (CO), hydrogen sulfide (H2S), and dust. These technologies can warn miners of immediately dangerous conditions within or prior to entering potentially hazardous areas. Laser-based technologies, such as the widely-deployed backscatter Tunable Diode Laser Absorption Spectroscopy (TDLAS) developed and commercialized by Physical Sciences Inc. (PSI) for natural gas leak surveying using handheld laser tools, enable sensing explosive or toxic environments from afar by safely illuminating the region of interest with a laser beam. In previous NIOSH/CDC/OMHSR research, we have demonstrated the use of this technology to detect areas of high methane concentrations along mine wall faces. Recently, we developed the ability to utilize this technology to create quantified images of small methane plumes, and to utilize the quantitative information to deduce the plume flux (i.e. emission flow rate). This proposed project is intended to incorporate this novel capability into lightweight handheld tools that enable visualization and quantification of potentially hazardous methane emission sources, as well as detection of stagnant methane pockets, in coal mines. These tools will enable warning of immediately dangerous conditions prior to miners entering a hazardous area as well as continuous inspection for explosive gas accumulations during cutting of mine face walls. The Phase I objectives are to: 1) develop an engineering prototype, and 2) evaluate the prototype in laboratory and research mine environments. The Phase I specific aims are to: 1) develop a prototype handheld imaging head with associated electronic components that can be used for field testing; 2) test the prototype; 3) analyze data and report results. Tasks to achieve these aims include: integrating laser beam launcher and steerer to the optical framework; integrating video camera; integrating computer for instrument control, data acquisition and processing; overlaying concentration maps and video images; implementing flux computation routines; completing tests in the laboratory and research mine, and; analyzing test results.